双路宽光谱近红外声光可调谐滤光器驱动系统设计

为满足双路宽光谱近红外声光可调谐滤光器(NIR-AOTF)对其驱动系统的要求,设计了一种基于高速单片机和直接数字频率合成器(DDS)的射频双驱动系统,采用软件查表法将各个频段驱动信号所对应的电压幅值控制字做成表并保存在单片机中,实现了DDS在各个频段的恒功率输出,使得NIR-AOTF在不同的波长衍射效率最佳;该系统主要由信号源模块、功率放大模块、射频开关模块及上位机控制模块组成,通过上位机下发频率、电压及信号通道控制字来产生两路功率恒定的射频信号,经过功率放大电路,驱动系统的输出信号功率可达33～ 35 dBm,使NIR-AOTF达到最佳工作状态,其0级光谱衍射效率测量值最高可达73％,驱动系统较好地满足设计要求.

Design of NIR-AOTF Drive System

In order to meet the double wide spectrum of near infrared acoustic optic tunable filter (NIR-AOTF) on its drive system,this paper designs a high speed MCU and direct digital frequency synthesizer (DDS) based on dual drive system of radio,using the software look-up table corresponding to each frequency band driving signal voltage amplitude control word made table and stored in the microcontroller,to achieve the DDS in the constant power output of each frequency band and the NIR-AOTF in different wavelength diffraction efficiency.The system mainly consists of signal source module,power amplifier module,RF switch module and PC control module,RF signal through the host computer under the frequency,voltage and signal channel control word to generate two constant power,through the power amplifier,the output signal power is 33 ～ 35dBm drive system,which makes NIR-AOTF achieve the best working conditions with the diffraction efficiency up to 73％,and that the driving system can meet the design requirements.